8
2.3
Supply Tubing
The supply tubing run should be as short as possible. For flooded suction mounting, install a
shut-off valve with an appropriate tubing connector at the tank outlet. Cut a length of tubing
from the coil supplied and install between the shut-off valve and the pump inlet fitting. For
suction lift applications, slide on the ceramic weight, then install a foot valve on one end of
suction tubing. Cut the tubing to a length such that the foot valve hangs vertically about 1 in
(25mm) above the bottom of the tank. Avoid any loops in the tubing run that could form a
vapor trap. Running the tubing through a length of pipe will help to keep tubing straight. Total
vertical suction lift should be no more than 5ft. (1.5m). Reference Figure 4.
Attach tubing as shown in Figure 5. First slide the coupling nut, small end first, onto the tubing.
Push the tubing over the valve housing tip
all the way to the valve housing shoulder
. (Tip: if the
tubing is stiff from cold, dip the tubing end in hot tap water for a few minutes so it will slide on
and flare out more easily. Push the coupling nut onto the threads. Apply some pressure on the
coupling nut and tubing while tightening the nut, making sure the tubing has not backed off of
the shoulder of the valve housing.
WARNING:
All fittings and coupling nuts should be tightened by hand only. If necessary, a
small tool may be used to make it snug. DO NOT use excessive force or large wrenches.
The coupling nut should not bottom out completely against the fitting. If this happens during
connection, either the tubing has slid down the shoulder while tightening, or the tubing has been
pinched. Remove the coupling nut, re-cut the tubing and re-connect.
Figure 4
Connecting Tubing
Foot
PVC Pipe Tubing
(user
Air Gap
Return
Point of
Injection
Injection
Valve
Coupling
Coupling Nut
(Air Vent
Coupling
